An Animal Model of Aspiration and Aspiration Pneumonia using LacZ Gene Expression in Lungs by Adenoviral vectors

To examine the relationship between disturbed upper airway reflexes and aspiration pneumonia, we administered a total volume of 20μl of Ad-CMV-lacZ (Ad vector) or 20μl of phosphate buffer solution (PBS) intranasal to C57 black mice. In nostrils, the lacZ gene expression was investigated in each mouse with or without anesthesia. Under anesthesia, the lacZ gene expression was detected by Xgal staining in the lungs of every mouse given the Ad vector. However, no gene expression was measured in the lungs of those given the Ad vector without anesthesia. In mice treated with PBS, there was no lacZ gene expression in the nostrils, trachea, or lungs, irrespective of anesthesia. These results suggest that unconsciousness or disturbed upper airway reflexes caused by anesthesia caused aspiration, resulting in an intranasal bolus that can reached the lower airways, This process can be analyzed in mice tracted with adenovirus vectors carrying the E. coli LacZ gene. Mice given Ad-CMV-lacZ transnasally can be used to study aspiration pneumonia in relation to unconsciousness.